Irregular-shank tools and drivers therefor

ABSTRACT

A tool ( 1 ) has a distal operative portion and a proximal shank ( 2 ) with a mounting portion ( 3 ), for mounting the tool in a holder ( 10 ). A substancial portion of the mounting portion has a cross-sectional shape with at least one and fewer than six 60-degree segments thereof having segment ends joined by a flat surface ( 5 ). The holder has a distal axial aperture or mounting hole ( 12 ) for receiving the tool ( 1 ), the aperture having a cross-sectional shape which has 60-degree segments thereof having segment ends joined by a flat surface ( 13 ), but no more such flat surface segments than those corresponding to flat surface segments of the tool. The holder further has a ball-detent ( 21 ) mechanism or other locking mechanism for engaging the mounting portion ( 3 ) of the tool ( 1 ).

TECHNICAL FIELD

[0001] This invention relates to tools such as drill bits, screwdriverbits, reamers, router bits, grinding wheels, spade bits, countersinks,mandrels, polishing tools, wheel brushes, wheel cutters and other toolaccessories, and to driving tools for same, for example a drill or ascrewdriver. In particular, the invention relates to tool configurationswhere the tool shanks have certain irregular (i.e. non-circular) shapesadapted to fit cooperative holder portions of the bit-driving tools.

DISCLOSURE OF INVENTION

[0002] It is an object of the invention to provide novel tools, andnovel holders for those tools for mounting on or incorporation in adriving implement, such as a hand tool or a power tool, the holderhaving a mounting hole and a retaining/locking mechanism which acceptsand securely holds a variety of tool shank mounting portions ofdifferent shapes. In the preferred embodiment of the tools, theircross-sections have at least one flat portion across at least a 60degree segment of the tool shank, to provide sufficient torque transferbetween the holder and the tool. The holder mounting hole has a numberof flats ranging from one to five corresponding to the number of flatportions on the mounting portion of the tool, the flat sections of thehole being tied together by substantially circular sections. A holderaccording to the invention can securely mount and hold not only toolshaving mounting portions according to the invention, but also standardhex tool bits, such as drill bits and screwdriver bits.

[0003] In the invention, the tool has a distal operative portion andproximal shank with a mounting portion, for mounting the tool in theholder portion of the driving tool. A substantial portion of themounting portion has a cross-sectional shape with at least one and fewerthan six 60-degree segments thereof having segment ends joined by a flatsurface. The holder has a distal axial aperture or mounting hole forreceiving the tool, the aperture having a cross-sectional shape whichhas 60-degree segments thereof having segment ends joined by a flatsurface, but no more such flat surface segments than those correspondingto flat surface segments of the tool.

[0004] In an alternative embodiment of the tool, the mounting portionthereof has a cross-sectional shape with at least one protrusiontherefrom, adapted for engagement in at least one slot in aperture ofthe holder, or has at least one slot therein, adapted for engagementwith at least one radially-inward protrusion in the aperture.

[0005] The invention encompasses not merely the tools, but also thetools and holders in combination.

[0006] The holder has locking means for engaging the mounting portion ofthe tool. The locking means either comprises manually operatedengagement means for locking the mounting portion in the holder, formanually engaging the engagement means in a locking position afterinsertion of a tool in the holder, or automatically operated engagementmeans for locking the mounting portion in the holder, the engagementmeans automatically engaging in a locking position around the tool whenthe tool is inserted into the holder.

[0007] In a preferred embodiment, the tool has two said 60-degreesegments having segment ends joined by a flat surface, the two segmentsbeing on opposite sides of the tool from each other.

[0008] Advantageously, a portion of the mounting portion has acircumferential groove extending at least partway around the mountingportion's circumference, adapted to receive locking means of a holder ofa bit-driving tool, such as a locking ball of a ball-detent mechanism.The groove may extend completely around the circumference, or may beonly in at least one of the flat surfaces. Alternatively, the groove maybe in a surface of the mounting portion other than any of the flatsurfaces. Any suitable ball-detent mechanism, combination ball detentand transition ball mechanism, or any other suitable locking means maybe used, including some locking means perhaps not presently known.Non-limited examples of such locking means may be seen, for example, inU.S. Pat. No. 6,199,872, U.S. Pat. No. 5,470,180, U.S. Pat. No.5,682,800 and U.S. Pat. No. 5,779,404, and in published internationalpatent application no. PCT/CA00/00521. Thus it should be clearlyappreciated that the invention resides in the novel tools, and in thecombination of the tools and appropriate holders, rather than in theholders themselves.

BRIEF DESCRIPTION OF DRAWINGS

[0009] In order that the invention may be more clearly understood,preferred embodiments thereof will now be described in detail by way ofexample, with reference to the accompanying drawings, in which:

[0010]FIG. 1A is an end view of a first embodiment of a tool having amounting portion of a shank according to the invention,

[0011]FIG. 1B is a side view of the tool of FIG. 1A,

[0012]FIG. 2A is an end view of a second embodiment of a tool having amounting portion of a shank according to the invention,

[0013]FIG. 2B is a side view of the tool of FIG. 2A,

[0014]FIG. 3A is an end view of a third embodiment of a tool having amounting portion of a shank according to the invention,

[0015]FIG. 3B is a side view of the tool of FIG. 3A,

[0016]FIG. 4A is an end view of a fourth embodiment of a tool having amounting portion of a shank according to the invention,

[0017]FIG. 4B is a side view of the tool of FIG. 4A,

[0018]FIG. 5A is an end view of a fifth embodiment of a tool having amounting portion of a shank according to the invention,

[0019]FIG. 5B is a side view of the tool of FIG. 5A,

[0020]FIG. 6A is an end view of a sixth embodiment of a tool having amounting portion of a shank according to the invention,

[0021]FIG. 6B is a side view of the tool of FIG. 6A,

[0022]FIG. 7A is an end view of a seventh embodiment of a tool having amounting portion of a shank according to the invention,

[0023]FIG. 7B is a side view of the tool of FIG. 7A,

[0024]FIG. 8A is an end view of an eighth embodiment of a tool having amounting portion of a shank according to the invention,

[0025]FIG. 8B is a side view of the tool of FIG. 8A,

[0026]FIG. 8C is an end view of a variation of the tool of FIG. 8A,

[0027]FIG. 8D is a side view of the tool of FIG. 8C,

[0028]FIG. 9A is an end view of a ninth embodiment of a tool having amounting portion of a shank according to the invention,

[0029]FIG. 9B is a side view of the tool of FIG. 9A,

[0030]FIG. 10A is a sectioned side view of a first embodiment of aholder according to the invention,

[0031]FIG. 10B is an end view of the holder of FIG. 10A,

[0032]FIG. 11A is a partially sectioned side view of a holder accordingto the invention in position for receiving a tool of FIGS. 2A and 2B,

[0033]FIG. 11B is a partially sectioned side view of the holder and toolof FIG. 11A, showing the mounted tool inside the holder,

[0034]FIG. 12A is a partially sectioned side view of a holder accordingto the invention in position for receiving a standard hex cross-sectiontool of known art (a drill bit),

[0035]FIG. 12B is a partially sectioned side view of the holder and toolof FIG. 12A, showing the mounted tool inside the holder,

[0036]FIG. 12C is an end view of the holder and tool of FIG. 12B as seenfrom line A-A, showing the mounted tool inside the holder,

[0037]FIG. 12D is an end view of the axial opening of the holder,

[0038]FIG. 13A is a partially sectioned side view of a holder accordingto the invention in position for receiving a further type of standardhex cross-section tool of known art (a screwdriver bit),

[0039]FIG. 13B is a partially sectioned side view of the holder and toolof FIG. 13A, showing the mounted tool inside the holder,

[0040]FIG. 13C is an end view of the holder and tool of FIG. 13B as seenfrom line B-B, showing the mounted tool inside the holder,

[0041]FIG. 14 is a perspective view of a mounting portion according toone embodiment of the invention,

[0042]FIG. 15 is a perspective view of a mounting portion according to afurther embodiment of the invention,

[0043]FIG. 16A is a side view of a tenth embodiment of a tool having amounting portion of a shank according to the invention,

[0044]FIG. 16B is an end view of the tool of FIG. 16A,

[0045]FIG. 17A is a side view of an eleventh embodiment of a tool havinga mounting portion of a shank according to the invention,

[0046]FIG. 17B is an end view of the tool of FIG. 17A,

[0047]FIG. 18A is a side view of a twelfth embodiment of a tool having amounting portion of a shank according to the invention,

[0048]FIG. 18B is an end view of the tool of FIG. 18A,

[0049]FIG. 19A is a side view of a thirteenth embodiment of a toolhaving a mounting portion of a shank according to the invention,

[0050]FIG. 19B is an end view of the tool of FIG. 19A,

[0051]FIG. 20A is a side view of a fourteenth embodiment of a toolhaving a mounting portion of a shank according to the invention,

[0052]FIG. 20B is an end view of the tool of FIG. 20A,

[0053]FIG. 20C is an end view of a variation of the tool of FIGS. 20Aand 20B, and

[0054]FIG. 20D is a side view of the FIG. 20C tool.

BEST MODES FOR CARRYING OUT THE INVENTION

[0055]FIGS. 1A to 9B show different embodiments of mounting portions oftool shanks according to the invention. The tool is shown as a drillbit, but any tool having a shank with a mounting portion can be used.Thus, any tools such as drill bits, screwdriver bits, reamers, routerbits, grinding wheels, spade bits, countersinks, mandrels, polishingtools, wheel brushes, wheel cutters etc. are suitable for being providedwith mounting portions according to the invention.

[0056] In FIGS. 1A and 1B a first embodiment of a mounting portion 3 ofa shank 2 of a tool 1 is shown. The shank is generally circular incross-section 7, and has one flat surface 5, which corresponds in widthto a 60 degree section of the shank. An optional retention groove 4 isarranged towards the outer end of the mounting portion, for cooperationwith locking means of a holder (described later).

[0057] A second embodiment of a mounting portion 3 of a shank 2 of atool 1 is shown in FIGS. 2A and 2B. This is the embodiment presentlypreferred by the applicants. It is very similar to the first embodiment,but has two flat portions 5 arranged opposite each other on the shank.The shank is generally circular in cross-section 7. An optionalretention groove 4 is arranged towards the outer end of the mountingportion.

[0058] A third embodiment of a mounting portion 3 of a shank 2 of a tool1 is shown in FIGS. 3A and 3B. The shank is generally rectangular incross-section, having two first flat portions 5′ arranged opposite eachother on the shank and two second generally flat portions 7′ connectingthe first flat portions. Each first flat portion 5′ corresponds in widthto a 60 degree section of the shank. An optional retention groove 4 isarranged towards the outer end of the mounting portion.

[0059]FIGS. 4A and 4B show a fourth embodiment of a mounting portion 3of a shank 2 of a tool 1. The shank is generally circular incross-section, with knurles/splines 6 arranged along at least asubstantial portion of the mounting portion. The knurles/splines arearranged to cooperate with special tool holders having a correspondinglyshaped hole, for enhanced torque transfer between holder and tool. Theshank has one flat surface 5, which corresponds in width to a 60 degreesection of the shank. An optional retention groove 4 is arranged towardsthe outer end of the mounting portion.

[0060]FIGS. 5A and 5B show a fifth embodiment of a mounting portion 3 ofa shank 2 of a tool 1. The shank is generally circular in cross-section7, with a keyway 6′ arranged along at least a substantial portion of themounting portion. The keyway is arranged to cooperate with special toolholders having a correspondingly shaped hole, for enhanced torquetransfer between holder and tool. The shank has one flat surface 5,which corresponds in width to a 60 degree section of the shank. Anoptional retention groove 4 is arranged towards the outer end of themounting portion.

[0061]FIGS. 6A and 6B show a sixth embodiment of a mounting portion 3 ofa shank 2 of a tool 1. The shank is generally circular in cross-section,with gear teeth 6″ arranged along at least a substantial portion of themounting portion. The gear teeth are arranged to cooperate with specialtool holders having a correspondingly shaped hole, for enhanced torquetransfer between holder and tool. The shank has one flat surface 5,which corresponds in width to a 60 degree section of the shank. Anoptional retention groove 4 is arranged towards the. outer end of themounting portion.

[0062]FIGS. 7A and 7B show a seventh embodiment of a mounting portion 3of a shank 2 of a tool 1. The shank is generally circular incross-section 7, with bevelled gear teeth 6′″ arranged at the proximalend of the mounting portion. The bevelled gear teeth are arranged tocooperate with special tool holders having a correspondingly shapedhole, for enhanced torque transfer between holder and tool. The shankhas one flat surface 5, which corresponds in width to a 60 degreesection of the shank. An optional retention groove 4 is arranged towardsthe outer end of the mounting portion.

[0063]FIGS. 8A to 8D show an eighth embodiment of a mounting portion 3of a shank 2 of a tool 1. The shank is generally circular incross-section 7. The shank has two flat surfaces 5, which correspond inwidth to a 60 degree section of the shank. Each flat surface has aprotruding wing 9 arranged on it, substantially in the middle of theflat surface and running longitudinally along at least a portion of themounting portion 3. The wings are arranged to cooperate with specialtool holders having a correspondingly shaped hole, for enhanced torquetransfer between holder and tool. An optional retention groove 4 isarranged towards the outer end of the mounting portion, and is eitherarranged only on the flat surfaces 5 (as shown in FIG. 8B) or around theentire circumference of the shank (as shown in FIG. 8D).

[0064]FIGS. 9A and 9B show a ninth embodiment of a mounting portion 3 ofa shank 2 of a tool 1. The shank is generally circular in cross-section7 along a major portion of the shank, with flat surfaces 5 arranged atonly the proximal end of the mounting portion. The flat surfaces arearranged to cooperate with special tool holders having a correspondinglyshaped hole, for enhanced torque transfer between holder and tool. Theflat surfaces 5 correspond in width to a 60 degree section of the shank.An optional retention groove 4 is arranged towards the outer end of themounting portion.

[0065]FIGS. 10A and 10B show a holder 10, which accepts tools havingshanks as previously described in FIGS. 1A to 9B. The invention in itsbroadest aspect is in no way limited to this particular holder, or toany specific holder. The holder comprises an elongate connector means 15and an outer sleeve 14. The sleeve preferably has a grip-enhancing cover17. The connector means is attachable to a power tool or hand tool (notshown) via a tool mount 11. The connector means 15 has a longitudinalhole 12, which has a cross-section corresponding to the cross-section ofthe mounting portion of the tool. Thus, depending upon the embodiment oftool for which the holder is to be used, the longitudinal hole has atleast one flat surface 13, the width of which corresponds to a 60 degreesegment of the total hole cross-section. Two flat surfaces are shown inFIG. 10B, making the holder suitable for tools according to the secondand third embodiments as described earlier. The part of the longitudinalhole which is not a flat surface is substantially circular incross-section, to accommodate tools having a hex cross-section and toolssimilar to the earlier described fourth, fifth, sixth and seventhembodiments, but having two opposite flat surfaces arranged on theshank. The torque transfer between the holder and the tool is performedessentially by the contacting flat surfaces of the holder and the tool,respectively. The connector means includes at least one radial hole 22,which cooperates with a substantially spherical locking ball 21 movablyarranged in the radial hole and which is prevented from fully enteringthe longitudinal hole 12 by a smaller diameter part 26 (bevelled end) ofthe radial hole 22. The locking ball cooperates with the circumferentialgroove 4 (as shown in FIGS. 1A to 9B) in the tool to lock the tool inplace when the tool is fully inserted into the holder 10. The outersleeve 14 is arranged to reciprocally slide over the connector means 15between two end positions, and has a stepped inside diameter, having asmaller diameter part facing the tool mount 11 and a larger diameterpart 25 facing the tool bit. A bevelled transition 28 is arrangedbetween the two different diameter parts. The bevelled transition isarranged to cooperate with at least one transition ball 23, which willbe described in detail later. A sleeve biasing means 16, for example acoil spring, is arranged to bias the sleeve 14 away from the tool mount11. The transition ball 23 is arranged in a transition hole 24 in theconnector means 15. The transition hole is substantially radial, andpreferably angled so that the bottom of the transition hole is arrangedfurther from the tool mount 11 than the top of the transition hole.Alternatively, the transition hole is substantially perpendicular to thelongitudinal hole 12. Thus, the transition ball 23, which has a diametersubstantially corresponding to the diameter of the transition hole 24,is slidable between a first position at the bottom of the transitionhole, to a second position protruding from the top of the transitionhole. The bevelled transition 28 is pressed against the transition ball23 by the sleeve biasing means 16.

[0066] In FIG. 11A, a tool 1 is held in position to be inserted into theholder 10. The locking ball 21′ is free to slide in the radial hole 22,because the larger diameter part 25 of the sleeve 14 is located adjacentthe locking ball. The sleeve biasing means 16 is pressing the sleeve andthe bevelled transition 28 against the transition ball 23, which is thusforced to the bottom of the transition hole. The sleeve is held in thisposition by a mechanism comprising a locking cavity 20, which cooperateswith a locking ring 19 arranged in a locking ring groove 20 arranged onthe elongate connector means 15, to limit the stroke of the slidingmovement of the sleeve along the elongate connector means in thedirection towards the tool mount by the locking ring blocking furthermovement because the locking ring contacts the edge of the lockingcavity (as shown in FIG. 11B), and in the direction towards the tool bythe bevelled transition 28 contacting the transition ball 23 in itsposition at the bottom of the transition hole, which protrudes enough toblock the movement of the sleeve 14 when the bevelled transitioncontacts the larger diameter portion of the elongate connector means(see FIG. 11A). In the latter position, the sleeve is prevented fromsliding towards the tool mount, under the biasing influence of thebiasing means 16, by the frictional forces present between the inside ofthe sleeve and the locking ring 19.

[0067] As is shown in FIG. 11B, the tool 1 is inserted into thelongitudinal hole 12. The inserted end of the tool will push thetransition ball 23 radially outwards in the transition hole 23. Thetransition ball is pressed by the inserted end of the tool bit, from itsposition at the bottom of the transition hole towards the sleeve and thebevelled transition 28, thus pressing the sleeve towards the tool mount.A locking portion 27 of the sleeve 14 effectively blocks the lockingball 21 from movement in the first radial hole 22, locking the tool 1 inthe longitudinal hole 12.

[0068] To release the locking ball 21, the sleeve 14 is pressed towardsthe tool 1, starting to release the locking ball by sliding the lockingportion 27 of the sleeve forwards. The bevelled transition 28 will pushthe transition ball 23 towards the tool bit, to thereby start pushingthe tool bit out of the longitudinal hole 12. The locking portion of thesleeve fully clears the locking ball, allowing the locking ball to slideup in the first radial hole 22 sufficiently to not protrude into thelongitudinal hole 12. This allows the tool 1 to be fully removed fromthe longitudinal hole. The transition ball 23 is seated in the firstposition in the transition hole 24, blocking any further movement of thesleeve 14 in the direction towards the tool insertion hole (longitudinalhole). As soon as the tool has left the longitudinal hole, the lockingball can enter the longitudinal hole and thus release the sleeve 14 forsliding towards the tool mount 11, but the sleeve is prevented fromsliding by the frictional forces between the sleeve and the lockingring, as described above. Thus, when inserting a tool bit into theholder, these frictional forces will have to be overcome by the userpushing the tool bit into the holder with a sufficient force to releasethe sleeve.

[0069]FIGS. 12A to 12C show the holder 10 according to the inventionused with a standard size drill bit 100 having a hex mounting portion101. All technical features of the holder are the same as earlierdescribed and have the same reference numerals. The hex cross-section ofthe drill bit fits without problems in the longitudinal hole 12 of theholder, with the two flat surfaces 13 making contact with two oppositesurfaces of the hex mounting portion and the corners between theremaining four hex flat surfaces making contact with the longitudinalhole's substantially circular surface. The mounting portion of the drillbit and its mounting groove 102 (corresponding to the groove 4 of theearlier described tools) interacts with the locking ball 21 and thetransition ball 23 of the holder as has been described for FIGS. 10A and10B. Thus, the holder according to the invention can be used togetherwith either the earlier described tools or a standard size hex mountingportion drill bit.

[0070]FIGS. 13A to 13C show the holder 10 according to the inventionused with a standard size screw bit 200 having a hex mounting portion201 and a mounting groove 202. All technical features of the holder arethe same as earlier described and have the same reference numerals. Thehex cross-section of the drill bit fits without problems in thelongitudinal hole 12 of the holder, with the two flat surfaces 13 makingcontact with two opposite surfaces of the hex mounting portion and thecorners between the remaining four hex flat surfaces making contact withthe longitudinal hole's substantially circular surface. The mountingportion of the drill bit and its mounting groove 202 (corresponding tothe groove 4 of the earlier described tools) interacts with the lockingball 21 and the transition ball 23 of the holder as has been describedfor FIGS. 10A and 10B. Thus, the holder according to the invention canbe used together with either the earlier described tools or a standardsize hex mounting portion screw bit.

[0071]FIG. 14 shows in detail a further embodiment of a mounting portion3 of a shank 2 of a tool 1 according to the invention. The groove 4 isarranged only on those portions of the shank which do not have the flatportions 5. Alternatively and as shown in FIG. 15, the mounting portion3 of a shank 2 of a tool 1 according to the invention has a groove 4arranged only on those portions of the shank which have the flatportions 5.

[0072]FIGS. 16A and 16B show a tenth embodiment of a mounting portion 3of a shank 2 of a tool 1. The shank is generally square in cross-sectionalong a major portion of the shank, with flat surfaces 5. The cornersmay be rounded or sharp. The flat surfaces are arranged to cooperatewith special tool holders having a correspondingly shaped hole, forenhanced torque transfer between holder and tool. The flat surfaces 5may correspond in width to a 60 degree section of the shank. An optionalretention groove 4 is arranged towards the outer end of the mountingportion.

[0073]FIGS. 17A and 17B show an eleventh embodiment of a mountingportion 3 of a shank 2 of a tool 1. The shank is generally triangular incross-section along a major portion of the shank, with flat surfaces 5with sharp or rounded corners. The flat surfaces are arranged tocooperate with special tool holders having a correspondingly shapedhole, for enhanced torque transfer between holder and tool. The flatsurfaces. 5 may correspond in width to a 60 degree section of the shank.An optional retention groove 4 is arranged towards the outer end of themounting portion.

[0074]FIGS. 18A and 18B show an eleventh embodiment of a mountingportion 3 of a shank 2 of a tool 1. The shank is generally triangular incross-section along a major portion of the shank, with outwardly curvedsurfaces 5. The curved surfaces are arranged to cooperate with specialtool holders having a correspondingly shaped, for enhanced torquetransfer between holder and tool. An optional retention groove 4 isarranged towards the outer end of the mounting portion.

[0075] A twelfth embodiment of a mounting portion 3 of a shank 2 of atool 1 is shown in FIGS. 19A and 19B. This embodiment is similar to thethird embodiment shown in FIGS. 3A and 3B. The shank is generallyrectangular in cross-section, having two first flat portions 5′ arrangedopposite each other on the shank and two second generally flat portions7′ connecting the first flat portions. Each first flat portion 5′corresponds in width to a 60 degree section of the shank. An optionalretention groove 4 is arranged towards the outer end of the mountingportion.

[0076] A thirteenth embodiment of a mounting portion 3 of a shank 2 of atool 1 is shown in FIGS. 20A to 20C. The shank is generally rectangularin cross-section, having two first flat portions 5′ arranged oppositeeach other on the shank and two second generally flat portions 7′connecting the first flat portions. Each first flat portion 5′corresponds in width to a 60 degree section of the shank. An optionalretention groove 4 is arranged towards the outer end of the mountingportion.

[0077] Alternatively, the holder has at least two flat portions in theholder hole, each flat portion corresponding to a section of between 60and 120 degrees of the hole. The holder can thus securely transfertorque to tools having correspondingly located and sized flat portionsof the shank of the tool.

[0078] The tools as described, when applied to a drill bit, have anumber of apparent advantages over the prior art known as two-piecedrill bits. The two-piece construction has an ordinary substantiallycircular cross-section drill mounted in a longitudinal hole in a hexcross-section mounting piece.

[0079] The combination of a tool and holder according to any of thedescribed embodiments of the invention adds safety to the use of thedevice, because the device automatically locks the tool bit in theholder after insertion. No action, other than the insertion itself, hasto be performed by the user to insert and lock the tool bit in place. Asa safeguard, the device has to be actively manipulated in order torelease the tool bit from the holder again, but the tool bit will beautomatically dislodged during this manipulation, so that the tool bitcan be removed from the holder using only one hand.

[0080] It will be appreciated that the above description relates to thepreferred embodiments by way of example only. Many variations on theinvention will be obvious to those knowledgeable in the field, and suchobvious variations are within the scope of the invention as describedand claimed, whether or not expressly described. For example, irregular,i.e. non-symmetrical, cross-sections may be used for both the shank andthe holder mounting hole. An L-shape or a triangular shape might beused, where at least one of the flat sides correspond to the flat of astandard hex bit/holder. Naturally, and this applies to all embodimentsof the invention, the at least one flat side of the shank used fortorque transfer may be substantially narrower than the correspondingflat of the holder mounting hole. The basic requirement of theshank/holder fit is that only a certain amount of lateral movement ofthe shank inside the holder is allowed, to accurately hold the toolduring operation.

[0081] In the preceding description and in the accompanying claims, itis intended that expressions such as “generally triangular” or“generally rectangular” or “generally square” should mean that theshapes are essentially so, but may have somewhat rounded surfaces,corners and/or edges, which still suggesting the overall shape.

[0082] Industrial Applicability

[0083] The invention provides tools having novel shanks for easy andsecure mounting in tool holders.

1. A tool having a distal operative portion and a proximal shank with amounting portion for mounting said tool in a holder of a tool driver viaan axial aperture in the holder, characterized by a length of saidmounting portion having a cross-sectional shape with at least one andfewer than six 60-degree segments thereof having segment ends joined bya non-circular surface, adapted for engagement in said aperture whensaid aperture has a cross-sectional shape which has at least one60-degree segment thereof having segment ends joined by a non-circularsurface, corresponding to at least one said non-circular surface of saidmounting portion, and no more such non-circular surface segments thanthose corresponding to said non-circular surface segments of said tool.2. A tool as recited in claim 1, wherein there are two said 60-degreesegments having segment ends joined by a flat surface, said two segmentsbeing on opposite sides of said mounting portion from each other.
 3. Atool as recited in claim 1, further characterized by a portion of saidmounting portion has a circumferential groove extending at least partwayaround the mounting portion's circumference, adapted to receive lockingmeans of said holder.
 4. A tool having a distal operative portion and aproximal shank with a mounting portion for mounting said tool in aholder of a tool driver via an axial aperture in the holder,characterized by a length of said mounting portion having across-sectional shape with at least one protrusion therefrom, adaptedfor engagement in at least one slot in aperture of said holder.
 5. Atool having a distal operative portion and a proximal shank with amounting portion for mounting said tool in a holder of a tool driver viaan axial aperture in the holder, characterized by a length of saidmounting portion having a cross-sectional shape with at least one slottherein, adapted for engagement with at least one radially-inwardprotrusion in said aperture.
 6. A tool as recited in claim 1, whereinsaid mounting portion is generally triangular in cross-section along amajor portion of the shank.
 7. A tool as recited in claim 6, whereinsurfaces defining said generally triangular shape are bulged outwardlysomewhat, rather than being linear as in a pure triangle.
 8. A tool asrecited in claim 1, wherein said mounting portion is generally square incross-section along a major portion of the shank.
 9. A combination of atool and a tool-driver having a holder with a distal axial aperture forreceiving said tool, said tool having a distal operative portion andproximal shank with a mounting portion, for mounting said tool in saidholder, a substantial portion of said mounting portion having across-sectional shape with at least two segments thereof having segmentends joined by a non-circular surface, said aperture having across-sectional shape which has at least two segments thereof havingsegment ends joined by a corresponding non-circular, but no more suchnon-circular surface segments than those corresponding to non-circularsurface segments of said tool, and including locking means for engagingsaid mounting portion, said at least two segments corresponding to anangle of between 60 and 120 degrees of said aperture.
 10. A combinationas recited in claim 9, wherein said non-circular surfaces are flat. 11.A combination as recited in claim 9, wherein said cross-sectional shapeof said aperture has two opposing flat 60-degree segments, the othersaid segments being circular, thereby defining a somewhat ovaloid shapecapable of receiving said tool bits having a variety of cross-sectionalshapes, including hexagonal, triangular, and said ovaloid shape.
 12. Acombination as recited in claim 9, wherein said locking means comprisesmanually operated engagement means for locking said mounting portion insaid holder, for manually engaging said engagement means in lockingposition after insertion of a tool in said holder.
 13. A combination asrecited in claim 9, wherein said locking means comprises engagementmeans which automatically lock said mounting portion in said holder,upon insertion of a tool in said holder.
 14. A combination as recited inclaim 9, wherein said locking means comprises a locking ball mechanism.